Important roles of the lower urinary tract are urine storage and voiding, which are regulated by a coordinated action of the bladder and the urethra. That is, during urine storage, the bladder smooth muscle is relaxed and the urethral smooth muscle and the urethral sphincter are contracted, whereby a state of high urethral resistance is maintained and urinary continence is thus maintained. On the other hand, during voiding, while the bladder smooth muscle is contracted, the urethral smooth muscle is relaxed, and contraction of the external urethral sphincter is also suppressed. Examples of dysfunctions in the lower urinary tract include urine storage dysfunctions such as overactive bladder in which urine cannot be retained during urine storage, and voiding dysfunctions in which urine cannot be drained sufficiently during voiding due to increase in the urethral resistance or decrease in the bladder contractile force. These two dysfunctions may develop simultaneously in some cases.
Voiding dysfunctions are caused by an increase in urethral resistance or a decrease in the bladder contractile force during voiding, and lead to voiding difficulty, straining during voiding, attenuation of the urinary stream, extension of voiding time, an increase in residual urine, a decrease in voiding efficiency, or the like. As a cause of an increase in urethral resistance, a voiding dysfunction associated with benign prostatic hyperplasia is well-known, which is characterized by partial obstruction of the urethra due to nodular hypertrophy of the prostate tissues. Adrenergic α1 receptor antagonists have now been used as therapeutic agents for the voiding dysfunction associated with benign prostatic hyperplasia (Pharmacology, 65, 119-128 (2002)). An increase in the urethral resistance is also caused by functional obstruction in detrusor-external urethral sphincter dyssynergia due to neurological diseases or neurological disorders, or the like. With patients with these diseases, the effectiveness of adrenergic α1 receptor antagonists is unclear (Journal of Pharmacological Sciences, 112, 121-127 (2010)).
On the other hand, as a factor for decreasing the bladder contractile force during voiding, increasing age, diabetes, benign prostatic hyperplasia, neurological diseases such as Parkinson's disease and multiple sclerosis, spinal cord injury, nerve damage caused by pelvic surgery, and the like are known (Reviews in Urology, 15, 11-22 (2013)). As a therapeutic drug for a decrease in the bladder contractile force during voiding, bethanechol chloride which is a non-selective muscarinic receptor agonist, distigmine bromide which is a choline esterase inhibitor, and the like are known. However, it is known that these drugs have cholinergic side effects, such as diarrhea, abdominal pain, sweating, and the like. In addition, cholinergic crisis is sometimes expressed as a serious side effect, and caution is therefore required for the use (UBRETID (registered trademark) tablet 5 mg package insert, Torii Pharmaceutical Co., Ltd., Besacolin (registered trademark) powder 5% package insert, Eisai Co., Ltd.).
In voiding dysfunctions caused by an increase in the urethral resistance or a decrease in the bladder contractile force as described above, residual urine after voiding may be observed in some cases. Increased residual urine may cause a decrease in effective bladder capacity, and thus cause overactive bladder symptoms such as urinary frequency, or severe symptoms such as hydronephrosis in some cases. Therefore, there is a demand for a therapeutic agent which is more effective on bladder and/or urinary tract diseases or symptoms thereof caused by an increase in the urethral resistance during voiding or a decrease in the bladder contractile force (Reviews in Urology, 15, 11-22 (2013)).
Melanocortins are peptides that are generated by the processing from proopiomelanocortin, and examples thereof include an adrenocorticotropic hormone, and α-, β-, and γ-melanocyte stimulating hormones (α-, β-, and γ-MSH). Five subtypes (MC1 to MC5) have hitherto been reported as a melanocortin receptor. Any of the subtypes belong to a G protein-conjugated receptor of a class A, and activates an adenylate cyclase via the Gs protein to increase the amount of cAMPs. The MC4 receptors are widely distributed in the central nervous system, and are known to play an important role in feeding behavior, energy metabolism regulation, sexual function, and the like (Journal of Pharmacological Sciences, 128, 53-55 (2006)).
As a representative MC4 receptor agonist, the following ones have been reported.
In Patent Document 1, it is disclosed that an MC receptor ligand represented by the following general formula is useful for eating disorder, sexual dysfunction, skin disorder, chronic pain, anxiety, depression, obesity, and the like.

(In the formula, A represents C5-7 cycloalkyl, aryl, or heteroaryl. For the other symbols, refer to Patent Document 1.)
In Patent Document 2, it is disclosed that an MC4 receptor agonist represented by the following general formula is useful for obesity, diabetes, female sexual dysfunction, erectile dysfunction, and the like.

(In the formula, R1 represents a C1-6 alkyl group, X represents —(CH2)n-phenyl or —(CH2)nC(R5)(R6)(R7), in which (CH2) may have a substituent such as C1-4 alkyl, R5 represents —(CH2)n-phenyl or the like, R6 represents H, R7 represents —(CH2)nN(R8)2, and m represents 0. For the other symbols, refer to Patent Document 2.)
In Patent Document 3, it is disclosed that an MC4 receptor modulator represented by the following general formula is useful for obesity, diabetes, male erectile dysfunction, or the like.

(For the symbols in the formula, refer to Patent Document 3.)
In Patent Document 4, it is disclosed that an MC4 receptor agonist represented by the following general formula is useful for obesity, diabetes, female sexual dysfunction, erectile dysfunction, or the like.

(For the symbols in the formula, refer to Patent Document 4.)
In Patent Document 5, it is disclosed that the MC4 receptor agonist is useful for lower urinary tract disorder, particularly urinary incontinence, and an MC4 receptor agonist represented by the following general formula is disclosed.

(For the symbols in the formula, refer to Patent Document 5.)
In Patent Document 5, it is described that the compound of Example 8 has an action of increasing the urethral pressure in the pharmacological data.
In Patent Document 6, it is disclosed that an MC4 receptor agonist represented by the following general formula is useful for sexual dysfunction, obesity, diabetes, lower urinary tract disorder, or the like.

(For the other symbols, refer to Patent Document 6.)
In Patent Document 7, it is disclosed that an MC4 receptor agonist represented by the following general formula is useful for sexual dysfunction, obesity, diabetes, lower urinary tract disorder, or the like.

(In the formula, R3 represents phenyl or pyridyl, and n represents 0 or 1. For the other symbols, refer to Patent Document 7.)